1. Technical Field
Generally, the present invention relates to an apparatus and a method for monitoring and controlling material levels within a container. More particularly, the present invention relates to automatic ice making machines and to control systems for adjusting the level of ice stored in a storage bin of an automatic ice making machine.
2. Related Art
Numerous devices and methods have been known and used for monitoring the amount of a material stored within a container. While many of these devices and methods produce quite accurate and reproducible results with respect to their monitoring function, they are less reliable when coupled with a means for regulating the amount of material delivered to, retained, or stored in a container. Frequently, the shortcomings of such monitoring and regulating devices are attributable to either the physical characteristics of the material being stored, the monitoring means, the regulating means or all of the foregoing. Thus, the physical state of the material being stored, a liquid, solid or gas, and the possible changes between these states of matter may have a significant effect both on monitoring of the material and regulation of the amount of material delivered to the storage container. In addition, both the means of monitoring such materials, including various sensors and related components, currently both mechanical and electrical in nature, vary with the conditions and nature of the material being regulated in how effective the overall system is in achieving its objectives.
Partly because of the inherent physical characteristics of ice, methods and devices for producing, regulating the production and storage of ice have proliferated in the twentieth century. Thus, both in the commercial production of ice and in home ice makers, devices are provided to monitor the level of ice in a storage container and to supply such information to the apparatus which actually produces the ice or delivers the ice to the storage container in a desired form. Such monitoring and control devices are employed in ice-making machines to avoid damage to the ice-producing device and as a convenience to users in avoiding overfilling and spillage from the ice storage bin. The physical characteristics of ice being a solid well below room temperature and being a liquid at and somewhat below room temperature has provided both the basis of monitoring and regulating devices and has also been associated with some of the shortcomings of such devices. Thus, a great number of sensors rely on the fact that ice is in the solid state when stored, while other devices depend on the temperature at which ice remains in the solid state.
Many of the devices currently used in ice machines for detecting and regulating the amount of ice stored within a reservoir type bin are not as effective in controlling the level of ice within a storage bin container as sought for both large scale commercial production ice making machines and small scale ice making machines used in the home environment. Other devices, while functioning both properly and efficiently, are either difficult to install or to remove for repair or replacement.
Many of the monitoring systems used for ice level control devices for the storage bins of ice machines employ sensors or monitors which are either substantially mechanical, thermostatic (temperature), ultrasonic, or photoelectric type sensors.
Typical mechanical type control systems employ a rod or lever to throw an electrical switch. When the level of ice delivered to a storage container reaches a specified height, it presses against the rod or lever, thereby repositioning the rod or lever to a cut-off position. Thus, the movement of the rod through a certain distance or the movement of the lever over a specified arc activates a proximity switch to terminate the ice making operation of the apparatus.
In the thermostatic type control systems, the thermostatic sensors are set so that when the ice reaches a certain height, it touches a capillary tube filled with a gas mixture. When the gas cools, it causes an attached diaphragm to move which in turn physically moves a switch from a closed to an open position. This signals the control timer for the given ice machine to terminate the ice-making functions. The temperature sensor can be fixed to the inner wall of the bin. The sensor can itself be inserted into the bin to directly contact with the ice when the ice reaches a predetermined level.
Contact types of level-monitoring sensor devices have problems associated with accuracy and reliability. Most such mechanical and thermostatic types of sensors are placed within the storage bin which they are intended to monitor and rely on contact with ice being stored within the storage bin. Accordingly, they are prone to damage both by contact with ice on a regular basis and moisture seeping into the moving parts and resulting in corrosion of the metallic components of the sensor. In addition, placement within the storage bin exposes such sensors to accidental contact with utensils placed in the storage bin to remove ice therefrom. Even relocating such sensors from the storage bin to locations such as in an ice guide barrel of a discharge port does not solve all of the problems associated with such mechanical and thermostatic devices and in some instances creates additional problems. Thus, even when such sensors are located within an ice guide barrel or delivery chute, particularly in auger-type ice-making machines, such devices still rely on contact between a portion of the sensor and ice being stored in order to activate a proximity switch. Accordingly, while such devices may avoid accidental damage due to contact with utensils in the storage bin, they are still exposed to potential jamming from ice particles and high humidity conditions. Furthermore, to avoid problems associated with particles of ice aggregating and forming larger masses of ice upstream from the mechanical or thermostatic sensors in ice guide barrels, between the sensor and the ice producing device, many ice making machines locate the mechanical and thermostatic sensors remote from the lower open end of the ice guide barrel and place the sensor at an upper end of the barrel closer to the source or feed of the ice and where a large head of ice is less likely to be formed and retained during long intervals between termination and actuation of the ice making device. While solving the problem of reducing accidental damage and allowing for delivery of ice with reduced clogging, this location is somewhat inaccessible and has the disadvantage of making installation, removal and repair more difficult.
Many non-contact sensor systems have been developed and used in recent years in ice storage level control systems. A number of systems use transducer level detectors, one type commonly encountered being an ultrasonic bin level system which compares a reference ultrasonic signal with a reflected signal. A switch is actuated at the desired ice level when the reflected signal overlaps the reference signal of the device. At that point, the reference signal is modified through feedback to prevent short cycling of the ice machine compressor.
Another type of non-contact sensor employed in ice making storage bins includes an xe2x80x9celectric-eyexe2x80x9d type system, also known as a light interrupter system. This type of sensor system employs a light source located within the storage bin and placed such that a beam of light from a source is focused on a sensor located across the bin. The ice making machine operates as long as the light source is detected by the sensor for a predetermined time period and terminates the operation of the ice making machine when the light source is interrupted for another predetermined time period. When ice supplied to the storage bin reaches a certain height, the light path is interrupted and the ice making device in the machine is terminated after a predetermined of time.
All of these non-contact sensor and level regulating systems used in ice making apparatuses are located within the ice storage bins of the apparatus and most have some of the same advantages and disadvantages as the contact-type sensors. Although non-contact sensor systems are generally not affected by some of the shortcomings of mechanical and thermostatic detection systems, some suffer, to a degree, from some of the problems which affect all sensors located within an ice storage bin, such as high moisture and humidity conditions.
While each of the above-described ice storage bin level detection and regulation systems functions satisfactorily under some conditions and many function well under most conditions, all have certain problems related to their nature and their location, that location most often being within the storage bin of the ice making apparatus.
What is sought at present, both in commercial ice making apparatuses and home ice making devices is an ice bin control system having a sensor which is durable, reliable, accurate, capable of withstanding both low temperatures and high humidity conditions encountered in ice making apparatuses, and is easily installed and accessible for removal, repair or replacement.
An object of the present invention is an ice making machine having an automatic switch which actuates the ice making device of the machine and which is controlled by a reliable, durable and accurate ice storage bin level sensor of a non-contact type that is so situated as to be minimally sensitive to humidity and temperature conditions. It is also an object of the present invention to provide an improved ice storage bin level sensor for controlling an ice making machine free of moving parts, which is located remote from the bin area. It is an additional object of the present invention to provide an ice storage bin level photoelectric sensor which includes both a light transmitter and receiver in the same unit which is adapted to be located remote from the ice storage bin. Still another object of the invention is to provide an automatic ice making machine employing such photoelectric sensor in a location which is remote from the ice storage bin but is also accessible for removal and installation.
It is also an object of the present invention to provide an ice storage level detecting apparatus, which can be manufactured and provided separately from an ice making machine and can be provided as a kit to be installed in new ice making machines or installed as a retrofit device in existing ice making machines. This ice storage level detecting apparatus has the same objects and features enumerated immediately above.
The aforementioned objects and other objects of the invention are achieved through various embodiments of the present invention described below.
A first aspect of the invention relates to an ice making machine which includes an ice making section, an ice discharge port connected to the ice making section for receiving ice made in the ice making section, an ice storage section for storing ice produced in the ice making section, an ice delivery chute interconnecting the ice discharge port and the ice storage section, and an ice storage level detecting apparatus including an ice storage level sensor disposed in the ice delivery chute proximate an outlet end of said ice delivery chute.
A further aspect of the invention relates to an ice storage level detecting apparatus for an ice making machine which includes an ice storage level sensor, a housing to receive the ice level storage sensor, the housing adapted to be affixed within an ice delivery chute of an ice making machine at or adjacent an outlet of the ice delivery chute.
Since the ice storage bin level sensor of the present invention includes no moving parts and is located remote from the ice storage bin, specifically within the ice storage chute, it remains free from damage during normal usage. It may also be adjusted to detect varying heights of ice such that when the ice in the storage bin reaches a predetermined height, the sensor sends a signal to the ice making device to terminate production of ice. Because the sensor is located remote from the ice storage bin, moisture resulting from contact with ice or condensed moisture does not collect on parts of the sensor.
In the present invention, no special timers are required as are typically used in apparatuses including interrupted beam type photoelectric sensors to allow for breakage of the light path when ice is removed from the storage beam. The sensor used in the present invention is based upon the reflection of a light beam from the surface of the ice within the storage bin which triggers the bin control circuitry. When ice reaches a predetermined height within the storage bin, a light beam is reflected from the surface of the ice and is transmitted to the receiver contained within the device, thereby completing the circuit and causing the sensor to actuate a switch terminating production of ice by the ice making device.